1. Field of the Invention
This invention relates to railroad car trucks and particularly to those trucks allowing relative movement between major components of the truck to occur during travel of the truck.
2. Prior Art
Railroad car trucks in popular use today include spaced side frames resiliently carrying ends of a transversely positioned bolster which in turn supports a body of the railroad car. At ends of each side frame are journaled axle ends of a front and a rear wheelset. Under such an arrangement, movement between the wheelsets, side frame and bolster is limited to rotation of the wheelset about its longitudinal axis and vertical movement between the bolster and the side frame.
Recognizing that while the rigidity of the above-described truck may be desirable while the truck is traveling over a straight section of track, this rigidity is not desirable when the truck must travel about a curved track section and particularly where the curved section is banked to allow a higher rate of travel.
To overcome this rigidity, various modified truck designs have been developed with one such modified truck disclosed in U.S. Pat. No. 2,737,907.